1. Field of the Invention
This invention relates to a floor panel for forming a floor covering, as well as to a method for manufacturing a floor panel.
2. Related Art
More particularly, the invention relates to a floor panel of the type wherein the floor panel comprises a substrate, which substrate preferably is manufactured on the basis of synthetic material; wherein this floor panel, on at least one pair of opposite edges, comprises coupling parts, which coupling parts allow that two such floor panels can be coupled to each other by means of a downward movement of one floor panel in respect to the other floor panel; wherein these coupling parts allow a locking in a first direction perpendicular to the plane of the floor panel, as well as in a second direction perpendicular to the edges and in the plane of the floor panel; wherein these coupling parts substantially are formed of the material of said substrate and are made in one piece therewith; wherein these coupling parts consist of a downward-directed upper hook-shaped part, which is situated on the one edge of said pair of opposite edges, as well as of an upward-directed lower hook-shaped part, which is situated on the other, opposite edge of said pair of opposite edges, which hook-shaped parts can be engaged behind each other by means of said downward movement; and wherein the upper hook-shaped part consists of a lip which is provided with a downward-directed locking element, whereas the lower hook-shaped part consists of a lip which is provided with an upward-directed locking element. Such floor panels are known, for example, from EP 2 339 092 A1 and WO 2010/023042.
A general problem with such floor panels is that the locking in vertical direction can be weak. As a result of this weak locking, it is possible that, under the influence of temperature, the individual floor panels set up and the coupling parts separate from each other or the floor panels move out of each other, whereby gaps may be created. This is due to shrinkage and expansion, or even warping, of the floor panels under the influence of temperature. The features of the floor panels of the state of the art are such that problems may occur already with heating by incident sunlight, for example, at a window in a room.